WRENCH-ENGINE MTG LOCK RING
"ENGINE MOUNTING,C" 1399504 $56.64

I have seen other folks make some type of one out of socket wrench head and cut notches, other bikes though.
Interesting all the images in the manual don't show the back with an area to put in a socket wrench.
Does anyone have one and is it just a steel pipe with notches? Has any one made one?